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  2. Tennis racket theorem - Wikipedia

    en.wikipedia.org/wiki/Tennis_racket_theorem

    The tennis racket theorem or intermediate axis theorem, is a kinetic phenomenon of classical mechanics which describes the movement of a rigid body with three distinct principal moments of inertia. It has also been dubbed the Dzhanibekov effect , after Soviet cosmonaut Vladimir Dzhanibekov , who noticed one of the theorem's logical consequences ...

  3. Vladimir Dzhanibekov - Wikipedia

    en.wikipedia.org/wiki/Vladimir_Dzhanibekov

    In 1985 he demonstrated stable and unstable rotation of a T-handle nut from the orbit, subsequently named the Dzhanibekov effect. The effect had been long known from the tennis racket theorem, which says that rotation about an object's intermediate principal axis is unstable while in free fall. In 1985 he was promoted to the rank of major ...

  4. Poinsot's ellipsoid - Wikipedia

    en.wikipedia.org/wiki/Poinsot's_ellipsoid

    As described in the tennis racket theorem, rotation of an object around its first or third principal axis is stable, while rotation around its second principal axis (or intermediate axis) is not. The motion is simplified in the case of an axisymmetric body, in which the moment of inertia is the same about two of the principal axes.

  5. Frenet–Serret formulas - Wikipedia

    en.wikipedia.org/wiki/Frenet–Serret_formulas

    A space curve; the vectors T, N, B; and the osculating plane spanned by T and N. In differential geometry, the Frenet–Serret formulas describe the kinematic properties of a particle moving along a differentiable curve in three-dimensional Euclidean space, or the geometric properties of the curve itself irrespective of any motion.

  6. Surface equivalence principle - Wikipedia

    en.wikipedia.org/wiki/Surface_equivalence_principle

    The principle yields an equivalent problem for a radiation problem by introducing an imaginary closed surface and fictitious surface current densities.It is an extension of Huygens–Fresnel principle, which describes each point on a wavefront as a spherical wave source.

  7. Jarzynski equality - Wikipedia

    en.wikipedia.org/wiki/Jarzynski_equality

    In thermodynamics, the free energy difference = between two states A and B is connected to the work W done on the system through the inequality: , with equality holding only in the case of a quasistatic process, i.e. when one takes the system from A to B infinitely slowly (such that all intermediate states are in thermodynamic equilibrium).

  8. Gauss–Codazzi equations - Wikipedia

    en.wikipedia.org/wiki/Gauss–Codazzi_equations

    In Riemannian geometry and pseudo-Riemannian geometry, the Gauss–Codazzi equations (also called the Gauss–Codazzi–Weingarten-Mainardi equations or Gauss–Peterson–Codazzi formulas [1]) are fundamental formulas that link together the induced metric and second fundamental form of a submanifold of (or immersion into) a Riemannian or pseudo-Riemannian manifold.

  9. Lifting-the-exponent lemma - Wikipedia

    en.wikipedia.org/wiki/Lifting-the-exponent_lemma

    The exact origins of the LTE lemma are unclear; the result, with its present name and form, has only come into focus within the last 10 to 20 years. [1] However, several key ideas used in its proof were known to Gauss and referenced in his Disquisitiones Arithmeticae. [2]